Binder‐Free NiCo(PO 4 ) 3 Nanosheet Electrode for Supercapattery With Enhanced Ion Transport and Long‐Term Stability

High-performance supercabattery based on reduced graphene oxide/metal organic framework nanocomposite decorated with palladium nanoparticles

Functionality of Fe(NO3)3 salts as both positive and negative pseudocapacitor electrodes in alkaline aqueous electrolyte

We present a facile one-step hydrothermal method to in situ grow nickel selenide (Ni3Se2) nanosheets on nickel (Ni) foam (Ni3Se2/Ni) by using SeO2 as selenide source, Ni foam as nickel source and NaBH4 as reducing agent. The mole ratio of NaBH4/SeO2 is optimized as 4:1. An asymmetric supercapacitor (ASC) is fabricated by using as synthesized Ni3Se2/Ni as positive electrode and activated carbon (AC) as negative electrode. The synthesized materials and assembled devices are measured and characterized by a field emission scanning electron microscopy, powder X-ray diffraction, cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The results shows that the as-synthesized Ni3Se2/Ni electrode possesses a high specific capacitance of 854 F g−1 at 1 A g−1. The ASC can steadily operate with a high voltage of 1.6 V in 3 M KOH electrolytes, and possesses a superior energy density of 23.3 W h kg−1 at a power density of 398.1 W kg−1. In addition, the Ni3Se2//AC ASC shows excellent charge/discharge stability, after 5000 cycles the capacitance retention reaches 91.11%. The excellent performance of Ni3Se2/Ni electrode is mainly due to the pseudo-capacitive by Ni3Se2 and the 3D structure of Ni foam.

Enhanced energy storage performance of copper intercalated redox active 1, 2, 4, 5-benzene-tetracarboxylic Acid organic framework

Metal-organic frameworks supported Ni–Co–S nanosheet arrays for advanced hybrid supercapacitors

Energy storage devices with high volumetric and gravimetric capacitance are in urgent demand due to the booming market of portable and wearable electronics. Using redox-active molecules as electrol...

A polyaniline/sulfonated graphene (PANI/SG) nanostructure was synthesized as electrode material for an asymmetric supercapacitor via a novel in situ chemical oxidative polymerization method including two oxidants. The composite’s structure and morphology were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) measurements. Furthermore, the electrochemical performances of the composite were characterized by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques in detail. In addition, we have triumphantly manufactured an asymmetric supercapacitor (ASC) employing activated carbon (AC) and PANI/SG as the positive and negative electrodes, respectively. The ASC possessed an extended potential window (1.4 V), a remarkable cycling property (85.9% capacitance retention after 5000 cycles), and a satisfactory average energy and power density (23 Wh/kg and 6.1 kW/kg).

Peering into Batteries: Electrochemical Insight Through In Situ and Operando Methods over Multiple Length Scales

Facile synthesis of hierarchical flower-like NiMoO4-CoMoO4 nanosheet arrays on nickel foam as an efficient electrode for high rate hybrid supercapacitors

Taking into account power needs for portable devices, the energy storage through electrochemical reactions seems to be a crucial technology, especially due to the growing technological advances requirements. Electrochemical capacitors have attracted great attention as promising energy storage devices because of their high power density and cycle life noticeably longer than batteries [i],[ii]. Recently, extensive works have been focused on enhancing both the energy and power density accompanied by reasonable cost of device production as well as its environment-friendly character. One of the approaches is idea initiated in 2001 [iii], of improving capacitors performance by merging advantages of capacitors and lithium-ion batteries. This procedure was aimed to increase the energy of the capacitor while maintaining the level of supplied power. Starting from 2001 till now in the literature we can find examples of different methods involving various electrode materials [iv],[v],[vi],[vii],[viii],[ix],[x]. Asymmetric supercapacitors composed of battery-type electrode and a high surface area carbon electrode [xi] combine the advantages and reduces the drawback of redox and capacitive based systems. Therefore, the asymmetric design offers the advantages of supercapacitors (power rate, cycle life) and batteries (energy density) [xii]. This work is focused on high-energy electrochemical capacitors utilizing chemically reduced graphite oxide (CRGO) as a negative electrode material and activated carbon (AC) with the well-developed surface area as a positive electrode material. For comparison, electrochemical characteristic of capacitors utilizing graphite negative electrode was also performed. The pre-lithiation process, made by electrochemical intercalation of lithium ions into graphite, has been chosen as the main method of negative electrode material preparing. Performed electrochemical measurements, i.e., cyclic voltammetry and galvanostatic charging/discharging presented improved energy efficiency compared with results for symmetric cells (i.e. AC/AC capacitor). All measurements were performed in the organic electrolyte to provide a wide range of operating voltage. In the case of the hybrid system energy density has been improved and exceed 90 Wh kg-1 accompanied by good power profile. Additionally, good cycle performance was also achieved. Chemically reduced graphite oxide (CRGO) displays excellent performance at current densities up to 8 A g-1and, therefore, it can be considered as a very promising material for high energy Lithium-ion capacitors (LICs). Moreover, for more detailed analysis, measurements in three-electrode cells were also conducted. Fig. 1 shows an example of cyclic voltammetry curves for two systems composed of activated carbon cathode and graphite or CRGO anode. For graphite anode, Faradaic reactions can be observed in very narrow working range (134 mV) comparing to the positive electrode (1266 mV). CRGO characteristics merge two mechanisms of lithium storage, namely, Faradaic and capacitive one. In result, the quite good proportion of working potentials between positive and negative electrodes (772 mV vs. 628 mV, respectively) can be seen. The intercalation of lithium ions into graphite material occurs relatively slowly, hence the difference in power between the electrochemical capacitors and lithium-ion batteries. The electrode with the slowest sweep of potential will determine the power of the device. In this case chemically reduced graphite oxide seems to be promising material as an anode in lithium ion capacitors due to the merged lithium insertion movement, that’s why the energy storage can take place comparatively fast, as in the positive electrode. Financial support from the project DEC-2013/09/D/ST5/03886 is gratefully acknowledged. Fig. 1. Comparison of working potentials positive and negative electrodes in hybrid systems AC/G(Li) and AC/CRGO(Li), obtained from cyclic voltammetry measurements. [i] A. Burke, J. Power Sources 91 (2000) 37 [ii] P. Simon, Y. Gogotsi, Nat. Mater. 7 (2008) 845 [iii] G.C. Amatucci, F. Badway, A.D. Pasquier, T. Zheng, J. Electrochem. Soc. 148 (2001) A930 [iv] D. Cericola, R. Kötz, Electrochimica Acta 72 (2012) 1 [v] W.J. Cao, J. Shih, J.P. Zheng, T. Doung, J. Power Sources 257 (2014) 388 [vi] S.R. Sivakkumar, A.G. Pandolfo, J. Appl. Electrochem. 44 (2014) 105 [vii] X. Sun, X. Zhang, H. Zhang, N. Xu, K. Wang, Y. Ma, J. Power Sources 270 (2014) 318 [viii] S. Dsoke, B. Fuchs, E. Gucciardi, M. Wohlfahrt-Mehrens, J. Power Sources 282 (2015) 385 [ix] J. Zhang, Z. Shi, J. Wang, J. Shi, J. Electroana. Chem. 747 (2015) 20 [x] K. Naoi, P.Simon, Electrochem. Soc. Interface 17 (1) (2008) 34 [xi] J.W. Long, D. Belanger, T. Brousse, W. Sugimoto, M.B. Sassin, O. Crosnier, MRS Bull. 36 (2011) 513 [xii] Z.J. Fan, J. Yan, T. Wei, L.J. Zhi, G.Q. Ning, T.Y. Li, F. Wei, Adv. Funct. Mater. 21 (2011) 2366 Figure 1

Synthesis of hexagonal boron nitride based PANI/h-BN and PANI-PPy/h-BN nanocomposites for efficient supercapacitors

Fabrication of hierarchical Mn-Co-P nanospheres as positive electrode material for ultra-stable asymmetric supercapacitor

Single-pot hydrothermal synthesis of copper molybdate nanosheet arrays as electrode materials for high areal-capacitance supercapacitor

Hierarchical three-dimensional nanoflower-like CuCo2O4@CuCo2S4@Co(OH)2 core-shell composites as supercapacitor electrode materials with ultrahigh specific capacitances

Hierarchical Ni–Co double hydroxide nanosheets on reduced graphene oxide self-assembled on Ni foam for high-energy hybrid supercapacitors